Clinical benefits of partial circulatory support in New York Heart Association Class IIIB and Early Class IV patients.

OBJECTIVE: Full mechanical support with a left-ventricular assist device (LVAD) is generally limited to end-stage heart-failure patients. We have been studying the safety and efficacy of the partial support Synergy® Pocket Micro-pump as bridge-to-transplant in a less-sick group of patients as a prelude to a study of its use for destination therapy. METHODS: The CircuLite® Synergy device is implanted via a small right-sided thoracotomy with an inflow cannula in the left atrium and an outflow graft connected to the right subclavian artery without the use of extracorporeal circulation. The micro-pump is the size of an AA battery, sits in the 'pacemaker' pocket subcutaneously in the right clavicular groove and pumps up to 3.0 l min⁻¹ from the left atrium to the right subclavian artery. RESULTS: The device has been implanted in 27 patients awaiting cardiac transplant (22 males), age 54.8 ± 10.0 years with ejection fraction (EF) 21 ± 6%, mean arterial pressure 73.5 ± 8.8 mm Hg, pulmonary capillary wedge pressure (PCWP) 27.5 ± 7.8 mm Hg and cardiac index (CI) 2.0 ± 0.4 l min⁻¹ m⁻². Duration of support has ranged from 6 to 281 days. Right-heart catheterization showed significant hemodynamic improvement in the short- and intermediate term after implant, with increases in CI from 2.0 ± 0.4 to 2.8 ± 0.6 l min⁻¹ m⁻² (p < 0.001) and reductions in PCWP from 28 ± 6 to 18 ± 7 mm Hg (p = 0.002) at an average of 9.5 ± 5.5 weeks. CONCLUSIONS: The Synergy device provides partial hemodynamic support and its use is associated with significantly improved hemodynamics, thus appearing to interrupt and partially reverse the progressive hemodynamic deterioration typical of end-stage heart failure. Ongoing efforts are aimed at demonstrating additional clinical benefits and continuing to further improve the risk/benefit ratio.

Pediatric heart support with a newly developed catheter based pulsatile 12F rotary blood pump: an animal study.

BACKGROUND: To evaluate mechanical and hematological compatibility of a pediatric, temporary left heart support system in a lamb model as a less traumatic alternative to the widely used ECMO. METHODS: A small, pulsatile rotary blood pump (target flow 0.5l/m at 80 mm Hg pressure head at 120 pulses per min) was inserted in six lambs (15.1+/-1 kg) via a left thoracotomy, through a purse string in the arcus aortae. With fluoroscopy the tip (=inflow) of the catheter was positioned in the outflow tract of the left ventricle. The outflow part was positioned immediately above the aortic valve. Animals were extubated at the end of the procedure. Mechanical and hematological parameters were followed for 14 days. RESULTS: Five animals survived a 2-week follow-up. One animal died because of empyema on day 6. Flow maintained stable (0.8+/-0.2l/m) in all animals during the evaluation period. Free hemoglobin as a parameter of hemolysis and hematocrit remained also stable. Necropsy revealed minimal fibrous reaction on one aortic valve leaflet in one animal and small hematoma formation in three. All animals showed mild signs of endothelial damage on the aortic arch at the level of the motor housing. One animal showed signs of old kidney infarction suggesting possible embolization during placement. CONCLUSION: This newly developed, catheter based, pediatric heart support system generates a stable flow for 14 days without compromising hematological stability and with acceptable tissue damage due to positioning of the catheter.